n-tier sequental access

hi guys , in n-tier there is sequental access from UI to BLL to DAL


but when we user linq can we say that UI can access the data source directly , it ot doext not voilate the convention ? or i am wrong some where .
because we can do like that in UI

Customer cus = Datacontext.gettable<customers.();
because if our UI need to know about Customer type so it should have reference of our datacontext class which is in seperate library.


i am confused because UI just need to know about customer type not its datacase method ? where is problem , am i wrong some where ?











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